Germs are tiny organisms that can cause infection. They are invisible to the human eye and exist everywhere — including in the air, soil and water, and on food, plants and animals. Some common types of germs are bacteria, viruses, yeasts and molds.

Germs have favorite places they like to live, different ways to spread, and their own unique ways of causing infections. Some can survive in the natural environment, while others prefer living in people or animals. Some thrive in the cold, while others need warmth.

All germs have one thing in common: when they find a place that is good for them to live, they set up a home for themselves
and multiply.